Mineral material, for example rock, is gained from the earth for processing by exploding or excavating. The mineral material can also be natural rock and gravel or construction waste such as concrete or bricks, or asphalt. Mobile crushers and stationary crushing applications are used in crushing. An excavator or wheeled loader loads the material to be crushed into the crusher's feed hopper from where the material to be crushed may fall in a crushing chamber of a crusher or a feeder moves the rock material towards the crusher.
Jaw crushers are suitable for example for coarse crushing at open pits or for crushing of construction waste. According to the function principle of the jaw crusher the crushing takes place between and against jaws, the so called fixed and movable jaws.
In a known jaw crusher a pitman is arranged movable relative to the frame of the crusher. An upper end of the pitman is supported by an eccentric to side walls of the frame of the jaw crusher. A rear end part of the frame is connected between the side walls. A lower end of the pitman is supported by a toggle plate to the rear end.
The toggle plate and a return rod are mounted between the lower end of the pitman and the rear end. The return rod is spring-tensioned and pulls the pitman backwards against the toggle plate and the toggle plate against the rear end. An example of a prior art jaw crusher with a rear end equipped with an adjusting apparatus for the toggle plate is shown in FIG. 1. Examples of known rear end cross sections are shown in FIGS. 2 and 3.
CN 201064720Y shows a jaw crusher having a frame with side walls which are connected to each other by a rear end part of the frame. A rear end of a toggle plate is supported by the rear end part. A wedge adjusting apparatus for the toggle plate is mounted between the toggle plate and the rear end part.
An object of the invention to provide new alternative technical alternatives by which drawbacks present in connection with prior art can be eliminated or at least reduced.